The colors are definitely blue/blue/orange, but the shade of repros is not true to the originals.
Repros are bright blue. The stock Nintendo blue buttons are more of a navy.
Repro orange is dark; Nintendo orange is a lighter shade.
See first pic.
It's not just the colors though that are different.
Nintendo plungers extend higher over the cylinder than those of repro buttons. This gives the Nintendos a deeper "push."
On the underside, the stem-end of the plunger (the end that makes contact with the microswitch) on a repro is a tiny bit longer than the stems on an original Nintendo. This causes a problem when using repro buttons with Nintendo switches. In the second pic, on the left you see a repro button mated with a Nintendo switch, which has a black ball on the end of the lever.
On the right is a repro button mated with a non-Nintendo switch, which does NOT have the ball on the lever.
The issue is that the ball on the Nintendo switches doesn't leave enough room for the button on the repros to release! The stem is too long. The switch stays closed when you're not pressing the button.
Anyway, if you wanna be sure what's going on ("are these original buttons or not?"), the shade should tell you. Look for navy blue/light orange. Or look at the stems and the microswitches. The Nintendo ones have the little ball-end levers and mate properly with the plunger on Nintendo buttons.
There was a Kickstarter recently to recreate the original Nintendo buttons. It failed.
https://www.kickstarter.com/projects/1423841610/donkey-kong-orange-and-blue-pushbuttons